Display screen or portion thereof with transitional graphical user interface



FIG. 1 is the first image in a sequence for a display screen or portion thereof with transitional graphical user interface showing our new design;

FIG. 2 is the second image thereof;

FIG. 3 is the third image thereof;

FIG. 4 is the fourth image thereof;

FIG. 5 is the fifth image thereof;

FIG. 6 is the sixth image thereof;

FIG. 7 is the first image of a display screen or portion thereof with graphical user interface showing our new design shown with additional broken lines showing environment;

FIG. 8 is the second image thereof;

FIG. 9 is the third image thereof;

FIG. 10 is the fourth image thereof;

FIG. 11 is the fifth image thereof; and,

FIG. 12 is the sixth image thereof.

The outermost dashed broken lines in the drawings illustrate the display screen or portion thereof and form no part of the claimed design. The dot-dash broken lines in the drawings represent a boundary of the claimed design that forms no part of the claimed design. The remainder of the dashed broken lines in the drawings illustrate portions of the graphical user interface that form no part of the claimed design.

The appearance of the transitional image sequentially transitions between the images shown in FIGS. 1-6 and FIGS. 7-12. The process or period in which one image transitions to another image forms no part of the claimed design. 

CLAIM The ornamental design for a display screen or portion thereof with transitional graphical user interface, as shown and described. 